First, I think anything you started saving prior to your decision to buy a home is YOUR money to do with as you please...

I totally agree. I'm sure he does too; I think he's trying to be helpful as "the house is the most important investment you can make." (This is clearly ingrained from his family.) But he knows I research these things, so if I come back to him and say I disagree because of XYZ, he'll probably see my point.

You are exactly right in that I want to show that it shouldn't be my only investment. My IRA is only finally getting back near breaking even. Though I'm glad I kept contributing to it, even during the down time. I should show him how that helped.